package com.xhdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.xhdp.config.RedissonConfig;
import com.xhdp.dto.Result;
import com.xhdp.entity.SeckillVoucher;
import com.xhdp.entity.VoucherOrder;
import com.xhdp.mapper.VoucherOrderMapper;
import com.xhdp.service.ISeckillVoucherService;
import com.xhdp.service.IVoucherOrderService;
import com.xhdp.utils.RedisIdWorker;
import com.xhdp.utils.SimpleRedisLock;
import com.xhdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author xiaohe
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService seckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @PostConstruct  //当前类初始化完毕后执行
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    private class VoucherOrderHandler implements Runnable {

        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    //获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    //判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明队列中没有消息，进入下一次循环
                        continue;
                    }
                    //解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //创建订单
                    proxy.createVoucherOrder(voucherOrder);
                    //ACK确认 XACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    //获取 pending-list 中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    //判断订单信息是否为空
                    if (list == null || list.isEmpty()) {
                        //如果获取失败，说明 pending-list 中没有消息，结束循环
                        break;
                    }
                    //解析数据
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(), true);
                    //创建订单
                    proxy.createVoucherOrder(voucherOrder);
                    //ACK确认 XACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理 pending-list 异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }

    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    //获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //下单
                    proxy.createVoucherOrder(voucherOrder);
                    //下单操作加锁
                    //handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/

    /**
     * 加锁创建订单
     * @param voucherOrder
     */
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        //创建锁对象
        RLock lock = redissonClient.getLock("order" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if (!isLock) {
            //获取失败
            log.error("不允许重复下单！");
            return;
        }
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;  //当前类的代理对象

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId = UserHolder.getUser().getId();
        //创建订单id
        long orderId = redisIdWorker.nextId("order");
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(), String.valueOf(orderId)
        );
        //判断结果是否为0
        if (result != 0) {
            //结果不为0，不能购买
            return Result.fail(result == 1 ? "库存不足！" : "不允许重复下单！");
        }
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString());
        //判断结果是否为0
        if (result != 0) {
            //结果不为0，不能购买
            return Result.fail(result == 1 ? "库存不足！" : "不允许重复下单！");
        }
        //结果为0，可以购买，保存下单信息到阻塞队列
        //创建订单
        long orderId = redisIdWorker.nextId("order");
        VoucherOrder voucherOrder = new VoucherOrder();
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        //存入阻塞队列
        orderTasks.add(voucherOrder);

        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //返回订单id
        return Result.ok(orderId);
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        //查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //判断是否存在
        if (count > 0) {
            log.error("用户已经购买过一次！");
            return;
        }
        //扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId).gt("stock", 0)
                .update();
        if (!success) {
            //扣减失败
            log.error("库存不足！");
            return;
        }
        //保存订单到数据库
        save(voucherOrder);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //判断秒杀是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始！");
        }
        //判断秒杀是否结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束！");
        }
        //判读库存是否充足
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足！");
        }

        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        // SimpleRedisLock lock = new SimpleRedisLock("order" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("order" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if (!isLock) {
            //获取失败
            return Result.fail("不允许重复下单！");
        }
        try {
            //获取代理对象（事务）
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }

    }*/

    /*@Transactional
    public Result createVoucherOrder(Long voucherId) {
        //一人一单
        Long userId = UserHolder.getUser().getId();
        //查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
        //判断是否存在
        if (count > 0) {
            return Result.fail("用户已经购买过一次了！");
        }
        //扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId).gt("stock", 0)
                .update();
        if (!success) {
            //扣减失败
            return Result.fail("库存不足！");
        }
        //创建订单
        long orderId = redisIdWorker.nextId("order");
        VoucherOrder order = new VoucherOrder();
        order.setId(orderId);
        order.setVoucherId(voucherId);
        order.setUserId(userId);
        save(order);
        //返回订单id
        return Result.ok(orderId);
    }*/

}
